Photo Gallery: Chalk Chrusher

The pictures are of a very large quarrying machine for crushing chalk to a useable size and depositing it onto a conveyor for transportation to the cement factory.

Two of these machines were installed in two chalk quarries serving the same cement factory, one in a quarry digging high chalk and one in a quarry digging low chalk. To manufacture the correct quality cement, differing amounts of each chalk must be mixed, as the chrushers were loaded by large earthmoving machines is could not be achieved easily manually.

The crushers were driven by very large closed loop hydraulic systems (450L/min @ 200Bar) driving B400 Staffa motors, these motors ran the conveyors that drove the chalk under the rotating crusher drums. The amount of chalk delivered could be varied by adjusting the speed of the motors by automatic radio signal from the factory over 2km away.

Both the hydraulic system and the crusher drum were driven by 200kw electric motors powered from the local National Grid pylons at 3,300 volts.

The hydraulic system also drove the tracks that the machine sits on at a max speed of 0.5kph which is fast enough when the machine is in normal use. However if the machine needs to be moved long distances a diesel driven power pack would be placed into the chalk hopper and two men can drive the machine by walking between the tracks, this is a very slow process, I know because I have driven the machine for 6 hours in very bad weather conditions.

Click image for close-up